1. Field of the Invention
This invention relates to tissue welding and more particularly to a method and apparatus for holding tissue sections in apposition and compression during application of energy to weld the sections together.
2. Description of the Related Art
Conventional surgical techniques typically require the use of sutures or staples to construct surgical connections that provide functional communication between living tissue structures. These surgical connections are generally referred to as "anastomoses". Anastomoses between cylindrical, especially tubular (i.e. hollow) structures are of significant clinical importance.
The problems associated with the utilization of sutures or staples are numerous. First, it is often time consuming and technically difficult to perform anastomoses by sutures or staples. This not only results in increased costs to the patient, a factor which cannot be overlooked as the current trend of skyrocketing health care costs continues, but creates a wide discrepancy in performance between surgeons, especially between experienced and novice surgeons. Second, the use of sutures and staples also means the introduction of "foreign bodies" which can cause trauma, inflammatory and immune response, and other adverse reactions due to the actual introduction as well as the prolonged presence of these foreign materials. Inflammation can actually cause a decrease in tensile strength and bursting strength of an anastomosis. Inadequate anastomoses pose a severe health risk to the patient if the sutured tubes or organs become sufficiently weak that they separate.
In an attempt to overcome these problems associated with sutures and staples, work recently began on the use of laser energy for welding the tubular and other types of tissue. It was discovered that properly applied laser light thermally induces intrinsic tissue changes which immediately produce hermetically sealed, strong bonds between the tissue. Such laser welding may also result in increased collagen synthesis, rapid restoration of tissue function, and enhanced healing. Additionally, advantageous for younger patients, laser welding allows the growth of welded seams as body size increases.
Thus, not only does laser tissue welding avoid the adverse effects associated with introducing foreign particles, i.e. sutures and staples, into the patient's body by avoidance of needle trauma and minimization of inflammatory and immune response, but laser welding can actually optimize the strength and functional characteristics of the anastomoses. Although laser energy is specifically addressed herein, the present invention contemplates energy sources of a broader magnitude including all applications of energy sufficient to affect tissue welding.
Still further, more automated energy tissue welding advantageously does not require the skill and time-consuming labor of the surgeon which is necessary for suturing and stapling. In fact, once the equipment is properly placed by the surgeon, a nurse or technician can simply switch the equipment on to provide the energy necessary to weld the tissue. This energy delivery technique requires no manual manipulation during the actual welding of the tissue and usually requires less than 10 seconds of welding time. Thus, a mechanical means for holding tissue during welding also provides an increased level of consistency which simply cannot be achieved in the individualized hand-manipulated suturing and stapling techniques or in less automated tissue welding techniques. The automated control of the energy welding parameters, rather than the skill or experience of a particular surgeon, determines the immediate success of the welding as well as the long term holding strength of the anastomosis.
The two essential criteria for successful energy welding are: (1) control of energy delivery and (2) tissue apposition. Control of energy (precision and consistency) is important to ensure that the desired amount of incoming energy is absorbed by the tissue. This means providing consistent energy density at a specific rate (i.e. fluence) over the entire anastomotic seam. Tissue apposition is critical since the ends of the hollow tubular sections to be welded must be in substantial abutment and accurate alignment to ensure that the energy effectively fuses the entire seam formed at the abutment. Substantial abutment also requires compression of the edges of the tubular sections. Deficient apposition can cause leakage or the formation of weak tissue bonds. Inadequate anastomoses can result in separation of the tissue sections, abnormal formation of fibrous tissue (adhesions) or undesired narrowing of the passage between the tubular sections (stenosis). The importance of tissue apposition cannot be overemphasized.
To date, many failed attempts at producing an effective energy anastomosis can be attributed to inadequate tissue approximation. Such inadequate welds have forced surgeons to rely on the use of "stay" sutures to assist in tissue alignment and orientation during welding. Such stay sutures, usually numbering at least three for each anastomosis, are typically left at the wound site and result in all of the accompanying drawbacks and deficiencies enumerated above. Therefore, there exists a need for a way to provide precise apposition of the ends of the tubular tissue sections to be welded as well as a need for maintaining the abutting tissue ends in this position during application of energy to the seam.
An apparatus and method for precisely aligning the tissue to create effective tissue welding would have a virtually limitless number of applications. For example, such apparatus could be used in reversing vasectomies (i.e. a refertilization procedure known as "vasovasostomy") by welding the severed ends of the vas deferens to re-establish communication, or used in fallopian tube anastomoses for reversing surgically-induced sterilization, or repairing defects to help allow women to achieve desired pregnancy. This is especially significant with the current high divorce rate, and the resulting number of remarriages, where many men and women seek to have a second family and thus require reversal of their surgical sterilization. An apparatus and method for performing these techniques by energy welding would provide an efficient, accurate and improved way to reverse sterilization, plus an increased success rate and reduced health risks to the patient. It would also result in increased consistency and decreased surgery time. Additional uses for such energy welding with the aforementioned advantages could include anastomoses for the bowel, ureters, urethra, blood vessels, biliary tissue, etc. In short, an apparatus for maintaining and securing tissue in close apposition and in correct alignment to enable accurate application of energy to weld the tissue sections would provide countless advantages over the prior surgical procedures of suturing and stapling and over the prior hand-manipulated tissue welding techniques.